Calculate how much time and interest you can save by making extra payments toward your mortgage principal.
Please enter valid positive numbers for all fields.
Original Payoff Date:
New Payoff Date:
Time Saved:
Total Interest Saved:
How Extra Mortgage Payments Save You Money
Paying off a mortgage early is one of the most effective guaranteed returns on investment available to homeowners. Because mortgages are amortized, the majority of your payments in the early years go toward interest rather than the principal balance. By making extra payments specifically designated for the principal, you reduce the balance on which future interest is calculated.
The Power of Compound Interest in Reverse
When you pay an extra $100 today, you aren't just reducing your debt by $100. You are eliminating the interest that $100 would have accrued over the remaining life of the loan. On a 30-year loan at 6-7% interest, a single dollar paid early can save you several dollars in interest costs over the long term.
Strategies for Early Payoff
Monthly Top-Up: Add a fixed amount (e.g., $100 or $200) to every monthly payment.
Bi-Weekly Payments: Splitting your monthly payment in half and paying every two weeks results in 26 half-payments per year, which equals 13 full monthly payments. This "extra" month of payment goes directly to the principal.
Windfalls: Applying tax refunds, work bonuses, or inheritance money as a lump sum principal payment.
Important Considerations
Before aggressively paying down your mortgage, consider the following:
Prepayment Penalties: Check your loan documents to ensure your lender does not charge a fee for paying off the loan early.
Emergency Fund: Ensure you have 3-6 months of expenses saved in liquid cash before locking money away in home equity.
High-Interest Debt: Pay off credit cards or personal loans with higher interest rates than your mortgage first.
Using This Calculator
Enter your current remaining balance (not the original loan amount), your current interest rate, and the years left on your term. The calculator assumes the extra payment is made every month starting from today until the loan is paid off.
function calculateMortgageSavings() {
// Get Inputs
var balanceInput = document.getElementById("currentBalance").value;
var rateInput = document.getElementById("interestRate").value;
var yearsInput = document.getElementById("remainingYears").value;
var extraInput = document.getElementById("extraPayment").value;
var errorDiv = document.getElementById("error-message");
var resultsDiv = document.getElementById("results-area");
// Parse Inputs
var balance = parseFloat(balanceInput);
var annualRate = parseFloat(rateInput);
var years = parseFloat(yearsInput);
var extraPayment = parseFloat(extraInput);
// Validation
if (isNaN(balance) || isNaN(annualRate) || isNaN(years) || balance <= 0 || annualRate < 0 || years <= 0) {
errorDiv.style.display = "block";
resultsDiv.style.display = "none";
return;
}
if (isNaN(extraPayment) || extraPayment 0) {
var interestForMonth = currentBalance * monthlyRate;
var principalForMonth = basePayment – interestForMonth;
var totalMonthlyPay = basePayment + extraPayment;
// Handle last month logic
if (currentBalance 1200) break;
}
// Calculate Savings
var interestSaved = totalInterestBase – totalInterestWithExtra;
var monthsSaved = totalMonths – monthsWithExtra;
// Format Date Strings
var today = new Date();
var originalPayoffDate = new Date(today.getFullYear(), today.getMonth() + totalMonths, today.getDate());
var newPayoffDate = new Date(today.getFullYear(), today.getMonth() + monthsWithExtra, today.getDate());
var options = { year: 'numeric', month: 'long' };
// Logic for formatting Years/Months saved text
var yearsSavedVal = Math.floor(monthsSaved / 12);
var remMonthsSavedVal = Math.round(monthsSaved % 12);
var timeSavedText = "";
if (yearsSavedVal > 0) {
timeSavedText += yearsSavedVal + (yearsSavedVal === 1 ? " Year" : " Years");
}
if (remMonthsSavedVal > 0) {
if (yearsSavedVal > 0) timeSavedText += ", ";
timeSavedText += remMonthsSavedVal + (remMonthsSavedVal === 1 ? " Month" : " Months");
}
if (timeSavedText === "") timeSavedText = "0 Months";
// Update DOM
document.getElementById("originalDate").innerText = originalPayoffDate.toLocaleDateString('en-US', options);
document.getElementById("newDate").innerText = newPayoffDate.toLocaleDateString('en-US', options);
document.getElementById("timeSaved").innerText = timeSavedText;
document.getElementById("interestSaved").innerText = "$" + interestSaved.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
// Show Results
resultsDiv.style.display = "block";
}